Joint for furniture construction



@cih 2, lgsz H Et JOHNSQN JOINT FOR FURNITURE CONSTRUCTION Filed March16, 1949 42W 36 K a 15W il fw@ W,

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Patented Oct. 21, 1952 JOINT FOR FURNITURE CONSTRUCTION Howard E.Johnson, South Ashburnham, Mass., assignor to W. F. Whitney Company,Inc., South Ashburnham, Mass., a corporation `ofv MassachusettsApplication March y16, 1949, Serial N0. 81,685

2 Claims.

rIhis invention relates to furniture construction and especially to theformation of concealed joints in articles of furniture.

The principal objects of the invention are to provide an improvedmortise and tenon joint for furniture which is of such construction asto afford a concealed joint; which will allow contraction and expansionof the joined parts without destruction of the joint; which provides fora stronger joint and for easier assembly ofthe parts; and which ismaterially less expensive to manufacture both from the standpoint ofeconomizing in time and material. Other and irnportant aspects of thejoint will appear hereinafter in connection with the descriptionthereof.

In accordance with this invention where two members, for examplestructural members of furniture, are to be joined togetherV in abuttingrelationship by a mortise and tenonjointone of the members has amortiseor open groove rabbeted or otherwise formed in itsr surface'extending inwardly from one of its edges, the'inner end of whichterminates short of any other edge. The greater portion of this groovehas spaced parallel side walls substantially at right angles to Near theinner terminal portion, the groove has re-entrant sidewalls and an endwall making acute angles with'the bottom the end wall being of generallysemicircular s'hape. The abutting edge ofthe other member constitutes atenen andV has locking and bearing portions extending therealong forAengagement with the groove, the former having sloping walls mating withthe re-entrant vside and end walls of the terminal portion of the grooveand the latter being of rectangular crosssection and having afree-sliding iit in that part of the groove having the parallel walls.The locking portion is set back from the end of the edge with which itis associated and lwhen engaged withinr the re-entrant walls of thegroove and brought into abutting engagement with its re-entrant closedend constitutes positioning means which controls the position of themembers, this preferably being predetermined to bringthe exposed edgesof the members flush with each other. Av binding material is employed tox the members in their assembled position, in the form of an adhesive,cement or the like applied solely to the locking portions of the mortiseand teno-n While the entire supporting protions of the mortise and tenonare devoid of a binder and hence free to come and go relative to eachother due to expansionor contraction of the members.

The invention will now be described in greater v2 detail with referencetothe accompanying drawings wherein: 1

Fig. 1 is an isometric fragmentary viewof an end portion of a piece offurniture embodying the improved joint construction showing a case endand several partition members;

Fig. '2 is a Vertical elevation of the inside of the case end showingthe mortises for the top, front and rear frame rails and a mortise forone of the intermediate partition members;

Fig. 3 is a plan view of a fragmentary portion of the top edge of thecase end shown in Fig. 1;

Fig. 4 is a vertical section on the line 4 4 of Fig. 2;

Fig. 5 is a vertical section on the line 5-5 of Fig. 2;V

Fig. 6 is a'vertical section on the line 6 5 of Fig. 2; l

Fig. 7 is a fragmentary plan view of a partition member showing a frontand side rail and the construction of the novel tenon at the lateraledge of the member;

' Fig. 8 is a bottom plan view of Fig. 7;

Fig. 9 is a top plan view of an assembledV case end and partitionmember, the case end being in section in a horizontal planesubstantiallyin the surface of the partition member;

Fig'. 10 is 'a section on the line IU-l of Fig. 9; and f l Fig. 11 is asection on the line ||ll of Fig. 9.

In the manufacture of furniture, particularly custom-built furniture,for example bureaus, desks, bookcases and other articles of furniture',it is desirable to' secure the component parte, that is for example,the' case end, yframe rails and partition frame members with concealedjoints, that is, jointvsywhich are not visible on the -face or othernormally exposed surfaceV of the furniture. For the purpose ofillustration only the novel joint'is shown therein as used in theconstruction of a bureau, a fragmentary portion at one end thereof beingshownV in'Fig. l1 wherein there is a vertical casev end Il) having atits 1ower edge spaced supporting legs I2,.t his case end being joined toa corresponding case end (not shown) spaced therefrom by top, front andback yframe rails M-M and intermediate vertically spaced partitionmembers IG-I' Which afford spaces in which may slide drawers. The frontand rear frame rails at the top of kthe case ends are joined thereto bymortise and tenori joints I8, only one of which is shown herein. Themortise I1 is rabbeted or otherwise formed in the inner face of the caseend by cutting in- Wardly from the top edge of the case end and at apoint spaced from the vertical edge thereof and is of dovetail crosssection (Fig. 3). The tenon I9 is formed at the end of the rail and hasa corresponding dovetail construction which mates with the mortise. Withthe foregoing construction the joint is concealed except as seen fromthe top of the case end and since a top Will be placed thereon the jointwill be completely concealed in the finished article.

The intermediate partition members I8 include front and back horizontalframe rails 20 extending across the front and rear vof the article fromcase end to case end and horizontal forwardly and rearwardly extendingVside frame rails 22-22. The rails 20-20'- and V2'2---22 are joined inconventional manner by tongue and groove joints to form a substantiallyrectangular frame Within which is placed and held a dust bottom 24, thelatter being set into the frame with its edges situated in grooves 26formed in the inner edges of the rails 20-20 and 22-22.

In accordance with the invention `the intermediate partition members I6are secured in vertically spaced relation so that the exposed edgesurfaces 28 of lthe front frame rails 20 will be flush with the forwardvertical edge surfaces 30 of the case end members I0. This isaccomplished herein by rabbeting horizontal, vertically spaced mortisesor grooves 34 (Fig. 2) ineach case end. Each mortise has an open orentrance end 34 at the rear 'edge 32 of the case end and extendstherefrom forwardly toward the front edge 30 terminating in a .closed orblind end 44 at a predetermined distance from the front edge 30 and hasa locking portion which serves to unite the parts and a supportingportion fwhich serves to carry the load. The supporting portion 36constitutes the major portion of the mortise, is of substantiallyrectangular cross section (Fig, 4) and has a bottom 38 andverticallyspaced parallel side walls 40. The locking portion 42 is situated at theforward end of the mortise and has, as shown in Fig. 45, a flat bottom38 forming a continuation of the bottom 38, reentrant side walls 42 andan end wall 44' inclined inwardly from the bottom and the parallel sides40, the end wall being semicircular. Ihe supporting portion 38 ofthemortise is made wide enough to receive the lateral edge of theintermediate partition member I6 therein with a freesli'cling fit, thatis vwith sufficient clearance so that swelling and shrinking ofthe partswill not cause binding. Alternatively if a narrow mortise is desired,the lateral edge of the intermediate portion may be rabbeted off on oneor both sides to fit freely into the mortise.

'Ihelateral edges of the intermediate members constitute tenons forengagement with the aforesaid mortises, each of which is divided intotwo portions, a locking portion and a supporting portion for engagementwith the locking and supporting portions thereof. The locking portion isformed by rabbeting each end of the front rail 20 to provide a dovetailtongue having sloping front and side walls 52 and 52 corresponding ininclination to the reentrant walls 42 and 44'. ns illustrated in Fig. 8,the inclined front wall 52 of the locking portion is spaced from thefront edge 28 of the rail a distance commensurate with the spacing ofthe inclined wall 44 at the end of the mortise from the front edge 30 ofthe case end so that when the members are assembled the surfaces 28 and30 will be flush. It is to be understood, however, that the surfacesneed not necessarily be flush 4 with each other but that they may besituated in any desired relation to each other. The end or edge of thelocking portion is planed off so that it is shorter than thecorresponding edge of the supporting portion 60. The supporting portion68 is substantially rectangular in crosssection, having parallelsurfaces which may be the normal top and bottom surfaces of the siderail or may be cut into the surfaces thereof by rabbeting to make thisportion thinner if the mortise is of smaller dimensions.l In any event,the supporting portion 60 should be thin enough to afford a free fitinto the mortise. A notch 58 is cut in the supporting portion 60 behindthe lockingv portion to provide a clearance space for the junctionbetween the rectangular and reentrant portions 3B and 42 of the mortise.

To assemble the parts adhesive is applied to the reentrant walls 42 and44 of the mortise and to the inclined walls 52-52 of the tenon, thepartition member I8 is placed substantially at right angles to thesurface of a case end I0 with its forward edge 28 at the rear entranceto the mortise 34, and is then slid along the mortise until the frontwall 52 is engaged with the closed reentrant wall 44 of the mortise. Itis to be observed that since the inclined walls 52 of the lockingportion 50 are set back from the surface of the supporting portion 60and that it is not as long as the portion 60, no part of the lockingportion 50 rubs against the bottom or walls of the rectangular portionof the mortise, and hence, when the tenon is entered into the mortise,the glue appliedY to the locking portion will not be scraped off ontothe bottom or walls of the mortise andy be llost or effect cementingwhere it is not desired. In this connection it is important that no gluebe applied to any part of the side walls or bottom of the mortise in thesupporting portion thereof.

Important aspects of the foregoing construction are that the parts mayeasily be assembled and will interlock so as to hold their respectivepositions during hardening or setting of the cementing` material withoutemploying clamps; that a positive interlocking of the parts is effectedby engagement of the locking elements which prevents separation of 'theparts even though the cement may ultimately dry out to such an e'xtentas to become ineffective; that the cemented part of the joint iscomparatively small so that expansion therein is comparatively small andhence there will be little opportunity for unequal expansion of thejoint and possible disruption thereof. The greater part of the jointwill be free to come and go with weather conditions and hence will notdisturb or distort the article as a whole.

It is to be understood that the present disclosure is for purpose ofillustration only and that this invention includes all modifications andequivalents which fall within the scope of the appended claims.

I claim:

l. In an article of furniture a joint connecting two parts in abuttingrelation, without interposition of adjunctive elements, characterized inthat one member has formed in it a mortise of given depth extendinginwardly from one edge and terminating short of any other edge, a majorportion of rsaid mortise being of rectangular cross section and theremainder near the terminal end having` inclined re-entrant walls, thatthe other member has at its abutting end an integrally formed tenon, aportion of which is of rectangular cross section and is slidably engagedWithin the rectangular portion of the mortse and another portion ofwhich has a dovetail cross section, the inclined walls of which are theconverse of that portion of the mortise having the re-entrant Walls andis situated therein and a body of bonding material uniting the inclinedwalls of the dovetail portion of the tenon with the inclined Walls ofthe mortise, said rectangular portion of the mortise and tenon beingfree of bonding 10 material and free to come and go relative to eachother.

2. A joint according to claim 1, wherein the extremity of the dovetailportion or the tenon terminates short of the plane of the bottom of 15the mortise.

HOWARD E. JOHNSON.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PAILNTS Number Name Date 24,361 Smith June 7, 1859 115,725Frayer June 6, 1871 260,703 Moore et al. July 4, 1882 1,378,197 SchwabMay 17, 1921 FOREIGN PATENTS Number Country Date 659,522 France Feb. 5,1929

